SEATTLE (AP) — It could be the gray skies and rain that dominate most of the year or the architecture of the stadium that traps the slightest scream. It even could be the caffeine jolt the region is known for producing.

Whatever the root cause, Seattle has become known for owning arguably the loudest venue in the NFL.

Need a testimonial? Just ask this week’s opponent, the New York Giants.

“Seattle’s noise is just on a whole different level,” said former Seahawks and current Giants safety Deon Grant.

Seattle’s never been considered a quiet city when it comes to its sports teams — at least when they’re playing well. But that ability to affect the outcome of a game was never more evident than during the Giants’ last two trips to the Pacific Northwest.

Five years ago, during Seattle’s run to the NFC championship and only Super Bowl appearance, the Seahawks pulled out a 24-21 overtime victory over the Giants thanks to three missed field goals by New York kicker Jay Feely.

But the lasting memory of that November afternoon was the Giants’ 11 false start penalties, when New York’s offensive line was unable to decipher Eli Manning’s hand gestures and silent count.

The league monitored Seattle’s crowd a year later when the Giants were about to come in for a second straight season after claims were made that Seattle was piping in artificial crowd noise.

When they met in September 2006, the Giants had only three false starts, but it wasn’t for lack of trying by Seattle’s fans, who reached near jet engine levels on decibel meters that day.

“Being in the league 15 years and going around to a bunch of stadiums, there are no fans that measure up to our fans,” Seattle safety Lawyer Milloy said.

Following the Giants’ meltdown in 2005, Seattle started taking great pride in counting the number of opposing false starts in games at Qwest Field. Opponents have 99 false starts at Qwest since the start of 2005, the most in the NFL, and it seems almost appropriate the mark could reach 100 with the Giants in town this week.

“As much as I would like to block these things out, I know myself and the rest of the guys who were there for those games have to make sure the guys around us are ready to go for this game,” tackle David Diehl said. “We don’t want that feeling on the trip home like we’ve had in the past. It’s a long enough flight as it is.”

Seattle’s home-field advantage largely comes from Qwest Field’s cantilever roofs along each sideline. The roofs hang over the upper deck behind each sideline and cover 70 percent of the 67,000 seats. They are supposedly designed to keep fans semi-dry during the many rainy games.

But effectively, they are noise traps that push the fans’ roars back onto the playing surface, making players’ ears ring and grandstands shake.

But Seattle being loud isn’t isolated to just Qwest Field or the Seahawks.

The Kingdome, the Seahawks previous home, was notorious for being a concrete cavern of noise for opponents.

Husky Stadium, where the University of Washington plays, is notorious for its shaking upper decks and television cameras having trouble remaining stable.

When the NBA was still in town, KeyArena was regarded as one of the noisier venues when the SuperSonics were playing well.

And the Sounders of MLS, in only their second year, have come closest to replicating a European soccer atmosphere in America, even catching the attention of Los Angeles Galaxy star David Beckham during the MLS playoffs last week.

“It’s like playing in front of a European crowd,” Beckham said. “The noise, the atmosphere, the excitement … and it’s great to play in.”

But the centerpiece remains the Seahawks. Since his introductory press conference in January, coach Pete Carroll has made a point, constantly, of how much of an impact Seattle’s fans have created.

“It’s definitely an advantage,” Milloy said. “Miami has the heat, Green Bay has the snow and we have our fans.”

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AP Sports Writer Tom Canavan in East Rutherford, N.J., contributed to this report.